Could changing the time of day you take blood pressure medications improve their effectiveness? Professor Tom MacDonald tells Thembi Nkala how he found out out.
High blood pressure (hypertension) affects one in four adults in the UK. Having high blood pressure, persistently equal to or above 140/90mmHg, significantly increases your risk of cardiovascular disease, including heart attack and stroke. Hypertension, which is increasingly common with age, poses a significant threat to the health of millions of people but, once diagnosed, can be managed well with medications.
A team of top researchers from across the UK, led by Professor Tom MacDonald and backed by a BHF research grant worth more than £1m, discovered if taking blood pressure tablets in the morning or the evening has more of an impact on your cardiovascular health.
Why might the time of day matter when taking your blood pressure medications?
The purpose of our research was to establish whether night-time dosing is better (or worse) than morning treatment
We know that taking blood pressure tablets in the morning is beneficial in controlling high blood pressure, but more recent findings (enabled by the use of 24-hour blood pressure monitoring) suggest that night-time dosing may have an even better effect. Patients with hypertension whose blood pressure dips during the night tend to experience fewer cardiovascular events compared with those whose blood pressure barely decreases. Essentially, those with constant high blood pressure day and night don’t do so well.
The purpose of our research was to study patients taking once-a-day blood pressure medication and establish whether night-time dosing is better (or worse) than morning treatment in preventing events such as heart attacks, stroke and deaths related to diseases of the heart and circulation. Participants were randomly allocated into two groups; one took their blood pressure tablets at night, while the other group took theirs in the morning.
Can you tell us about the recruitment process for this study?
Recruitment to the study was open to anyone who took tablets for blood pressure once daily. We recruited over 20,000 participants of as varied demographics as possible (including 249 people who heard about the study through previous coverage in Heart Matters) and studied them over a period of five years. A study of this size and duration enabled us to know with confidence whether or not the time you take your medication is important. Patients were invited through GP surgeries, hospitals and social media from all across the UK to participate.
£1 million was the value of the BHF grant for Professor Tom MacDonald’s research
Patients who took blood pressure medication twice daily (morning and evening), those who did night-shift work or those in other clinical trials weren't able to take part in the study.
Participants also needed to have regular access to the internet, as this study was done by email and through a link to a secure website. Although this excluded a certain proportion of patients, for practical and financial reasons it would've been difficult to do a study of this size in the conventional way, where participants were seen by a clinician regularly. Previous studies that have used the web-based method found that correspondence was high-quality and cost-effective.
Will the participants’ records be safe?
We used a website that was set up for this study and the data was stored as securely as possible. We had to indicate that we have secure data protection measures before this study was approved. We employed computer experts (known as ethical hackers) who deliberately attacked our computer security system to test for any flaws we might have overlooked. Personal data was treated with the strictest confidentiality by the staff working on the study, and the publication of the results of the study didn't include any identifiable details about participants.
What did you find out and how can this research help patients?
The results of our study showed that there was no significant difference in the number of people who had a heart attack, stroke or died between the two groups - 362 in the morning group versus 390 in the evening. This indicates blood pressure medication is equally effective whether taken in the morning or evening.Currently, there’s no set guidance on when you should take your blood pressure tablets. Based on these results, people can take their blood pressure lowering medications at a time of day that’s convenient and that minimises undesirable effects. It’s still important to take them regularly as your doctor has recommended for you
We’d like to thank the BHF, which funded this study, and the British Hypertension Society, which co-ordinated it.
Professor Tom MacDonald
Professor Tom MacDonaldProfessor MacDonald is a Professor of Clinical Pharmacology and Pharmacoepidemiology at Dundee University, as well as a Consultant Physician at Ninewells Hospital and Medical School. Professor MacDonald is also President of the British Hypertension Society.
Can I get help with paying my prescription?
Medical prescriptions are free in Northern Ireland, Scotland and Wales. They are also free for people in England who meet certain criteria, including people who are:
- under 16 or over 60
- receiving Income Support, JSA, ESA or Universal Credit
- pregnant
- 16-18 and in full-time education
- and/or have certain health conditions, including a continuing disability or diabetes that can't be controlled with diet.
If you aren’t entitled to free prescriptions for your medicines you might be able to save money by buying a Prescription Prepayment Certificate (PPC).
getting help with prescription costs
